I can not run the installer it downloads 2.25 GB to my computer when I click run then it declares that the installer was not intended to run on my computer. If I save it to my drive and try to run it...

I keep trying to download the game after I bought it and it says the file is not ment to run on my computer.
I have a PC with quad amd 64 3.0ghz Procesor
am I to advanced? Because it erases the file...